Knocking noise under the hood?

If it were a clicking noise my original thought would be that its lifters or something and after getting the oil circulated the noise goes away, which honestly isnt a problem, doesnt harm the vehicle.

However, if its a knocking sound, that doesnt increase speed as vehicle increases rpm then its something external that could be exhaust as previously mentioned, enginge mounts, anything of the sort that can be moved by vibrations, its hard to diagnose this without being there in person to determine the sound and from experience determine is possible cause.

ADDED NOTE

As far as the oil recommendation, it will all vary according to mechanic and almost each has their reasons and all or most may be valid reasons. However, if you are using one type of oil, I would say stay consistent using that oil.

Main thing to look for is the same brand but different viscosity like, 5w-30 is a common viscosity.

If you use synthetic, thats a good type to go for until you put some miles on your engine, then I'de recommend switching to a non-synthetic.

Many people will disagree with that, but my reasons I say that have proven to be correct from my experience.

As the vehicle gets older your piston rings will degrade and gradually let organic and non-organic materials bypass them(thats common nothing abnormal).

Synthetic although a good lubricant doesnt do as sufficient of a job at distilling the chemicals that bypass your rings.

A non-synthetic however will distill those chemicals better so your engine in turn would last alot longer since the chemicals are unable to become a strong acid and eat gradually degrade your engine.

Keep using your original oil I would say, if you use valvoline, go for the standard napa brand, its the same thing as valvoline just a tad bit cheaper sometimes.

If it doesn't speed up with the engine revs, it could be a loose exhaust or something that knocks with the vibration, or maybe the fan hitting the shroud if it's an electric fan. I don't know what to do other than to get on the ground, and look underneath. Wait until the car is cold, and see if the exhaust is loose (you might need to jack it up to reach). Look at the fan and shroud and see if there's any sign of it hitting anything. But my money's on the exhaust. You may even be able to tell by shaking the tailpipe; if you hear it hitting anything, you'll know.

sounds like you piston is knocking or a bad push rod or rocker arm. are you burning oil a blueish smoke coming out of the exhaust. i would go ahead and do an oil change,oil filter, use a a high mileage engine oil and synthetic.

maybe a heat shield is too close to the exhaust pipe and when it gets hot then it goes away from the pipe. crawl under it and check it while it,s cold.

Do you drive extremely fast with your high beams on and honk at everybody? If you do, then you are probably doing something else wrong and it doesn't matter what the noise is because something else will break. Learn to drive

its because its a Chrysler product. If you had a chevy cobalt you would not be having these issues.

Da boys said u need to learn to drive. Best solution.

it might be that you have a slight pinhole in the upper part of the exaust pipe

sorry- i can't resist ;)

It is probably that chinese dragon I keep hearing so much about.